1. Field of the Invention
The present invention relates to a hydrostatic transaxle including a housing incorporating an axle and a hydraulic motor for driving the axle.
2. Related Art
Conventionally, as disclosed in U.S. 2006-225927 A1, there is a well-known hydrostatic transaxle including a housing in which an axial piston type hydraulic motor and an axle driven by the hydraulic motor are disposed. The housing incorporates a brake system including a brake rotor disposed on a motor shaft on the rotary axis of the hydraulic motor.
The brake system including the brake rotor disposed in the housing is a wet brake which is advantageous in performance and stability. However, the wet brake is expensive and has poor maintenancability. On the other hand, a dry brake is noticeable in its inexpensiveness to be exposed on the housing of the transaxle. However, in comparison with the wet brake, the dry brake is disadvantageous in performance and stability after all. If a hydrostatic transaxle is standardized so as to correspond to whether it has a wet brake in its housing or a dry brake disposed outside of the housing, the hydrostatic transaxle is greatly advantageous in economy. Further, with respect to the conventional hydrostatic transaxle, if rotary speed and direction of axles has to be detected for providing a steer-by-wire control system, the housing has to be formed to have a hole or the like for mounting a rotary speed sensor, so as to increase the number of manufacturing processes and costs. If the above-mentioned standardization corresponds to mounting of the rotary speed sensor, the transaxle is further advantageous in economy.